freemartin

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freemartin

(frē′mär′tn)
n.
A female animal, usually a calf, that is born as the twin of a male animal and is sterile because of having abnormal internal reproductive organs.

freemartin

a female twin born with a male, in which normal female sexual development has been adversely affected by hormones produced by the male twin.

freemartin

a sterile female born co-twin with a male. Occurs most commonly in cattle, very rarely in sheep, and apparently not at all in the other species. Male hormones produced by the male calf share the common circulation and inhibit the normal development of genitalia of the female. The female is also an erythrocytic chimera and can be diagnosed as a freemartin by this means. It can also be diagnosed by cytogenetic techniques. It produces white cells with XY as well as cells with XX chromosomes. Structural changes of nonpatent vagina, small vulva, cordlike uterus and hypoplastic ovaries are diagnostic but inconsistent. Some freemartins are quite normal clinically but all are sterile.
Enlarge picture
Freemartin placenta. By permission from Buergelt CD, Color Atlas of Reproductive Pathology of Domestic Animal, Mosby, 1996
References in periodicals archive ?
Hence, they could not be freemartins, yet they inherited Y chromosome material from somewhere, most likely from their fathers.
The Veterinary Diagnostic Laboratory at the University of Minnesota tests blood samples to determine if suspected freemartins are actually breeding heifers.
Unfortunately, this concept runs into two problems: the low rate of multiple births and freemartins.